U.S. patent application number 14/032138 was filed with the patent office on 2014-03-27 for method for in situ cleaning of mocvd reaction chamber.
This patent application is currently assigned to Advanced Micro-Fabrication Equipment Inc, Shanghai. The applicant listed for this patent is Advanced Micro-Fabrication Equipment Inc, Shanghai. Invention is credited to Zhiyou Du, Shuang Meng, Haruhisa Takiguchi, Yang Wang, Songlin Xu, Gerald Zheyao Yin, Ying Zhang, Ban Zhu.
Application Number | 20140083453 14/032138 |
Document ID | / |
Family ID | 47572118 |
Filed Date | 2014-03-27 |
United States Patent
Application |
20140083453 |
Kind Code |
A1 |
Yin; Gerald Zheyao ; et
al. |
March 27, 2014 |
METHOD FOR IN SITU CLEANING OF MOCVD REACTION CHAMBER
Abstract
A method for in situ cleaning of a Metal-Organic Chemical Vapor
Deposition reaction chamber is provided in embodiments of the
present invention. The method includes: introducing a first
cleaning gas into the reaction chamber, converting the first
cleaning gas into first plasma inside the reaction chamber to
completely remove a carbonaceous organic substance inside the
reaction chamber, wherein the first cleaning gas includes a first
oxygen-containing gas; and introducing a second cleaning gas into
the reaction chamber, and converting the second cleaning gas into
second plasma inside the reaction chamber to completely remove a
metallic oxide inside the reaction chamber, wherein the second
cleaning gas includes a first halogen-containing gas.
Inventors: |
Yin; Gerald Zheyao;
(Shanghai, CN) ; Du; Zhiyou; (Shanghai, CN)
; Meng; Shuang; (Shanghai, CN) ; Wang; Yang;
(Shanghai, CN) ; Zhang; Ying; (Shanghai, CN)
; Xu; Songlin; (Shanghai, CN) ; Zhu; Ban;
(Shanghai, CN) ; Takiguchi; Haruhisa; (Shanghai,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Advanced Micro-Fabrication Equipment Inc, Shanghai |
Shanghai |
|
CN |
|
|
Assignee: |
Advanced Micro-Fabrication
Equipment Inc, Shanghai
Shanghai
CN
|
Family ID: |
47572118 |
Appl. No.: |
14/032138 |
Filed: |
September 19, 2013 |
Current U.S.
Class: |
134/1.1 |
Current CPC
Class: |
H01J 37/32862 20130101;
C23C 16/4405 20130101 |
Class at
Publication: |
134/1.1 |
International
Class: |
C23C 16/44 20060101
C23C016/44 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 26, 2012 |
CN |
201210364958.X |
Claims
1. A method for in situ cleaning of a Metal-Organic Chemical Vapor
Deposition reaction chamber, comprising: performing Step a,
comprising: introducing a first cleaning gas into the reaction
chamber, and converting the first cleaning gas into a first plasma
inside the reaction chamber; and/or, converting the first cleaning
gas into the first plasma outside the reaction chamber and
introducing the first plasma into the reaction chamber; and/or,
introducing the first cleaning gas into the reaction chamber and
maintaining a temperature inside the reaction chamber in a range of
200.degree. C. to 500.degree. C.; and maintaining a pressure inside
the reaction chamber in a first predetermined pressure range for a
first time period to completely remove a carbonaceous organic
substance inside the reaction chamber and convert a metal and its
compound inside the reaction chamber into a metallic oxide, wherein
the first cleaning gas comprises a first oxygen-containing gas; and
performing Step b, comprising: introducing a second cleaning gas
into the reaction chamber, and converting the second cleaning gas
into a second plasma inside the reaction chamber; and/or,
converting the second cleaning gas into the second plasma outside
the reaction chamber and introducing the second plasma into the
reaction chamber; and/or, introducing the second cleaning gas into
the reaction chamber and maintaining the temperature inside the
reaction chamber in a range of 200.degree. C. to 500.degree. C.;
and maintaining the pressure inside the reaction chamber in a
second predetermined pressure range for a second time period to
completely remove the metallic oxide inside the reaction chamber,
wherein the second cleaning gas comprises a first
halogen-containing gas.
2. The method according to claim 1, wherein the first cleaning gas
further comprises Ar; and/or, the second cleaning gas further
comprises Ar.
3. The method according to claim 1, wherein the first cleaning gas
further comprises a second halogen-containing gas, and the second
halogen-containing gas comprises one of HCl, BCl.sub.3, Cl.sub.2, a
gas mixture of H.sub.2/Cl.sub.2, HBr or any combination
thereof.
4. The method according to claim 3, wherein, in the first cleaning
gas, the mole fraction of the first oxygen-containing gas is larger
than the mole fraction of the second halogen-containing gas.
5. The method according to claim 1, wherein the second cleaning gas
further comprises a second oxygen-containing gas, and the second
oxygen-containing gas comprises one of O.sub.2, O.sub.3, CO.sub.2,
H.sub.2O.sub.2, N.sub.2O, CO or any combination thereof
6. The method according to claim 5, wherein, in the second cleaning
gas, the mole fraction of the first halogen-containing gas is
larger than the mole fraction of the second oxygen-containing
gas.
7. The method according to claim 1, wherein the first
oxygen-containing gas comprises one of O.sub.2, O.sub.3, CO.sub.2,
H.sub.2O.sub.2, N.sub.2O or any combination thereof
8. The method according to claim 1, wherein the first
halogen-containing gas comprises one of HCl, BCl.sub.3, a gas
mixture of BCl/O.sub.2, a gas mixture of H.sub.2/Cl.sub.2,
Cl.sub.2, HBr or any combination thereof.
9. The method according to claim 1, wherein the first time period
is longer than 5 minutes and the second time period is longer than
3 minutes.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority to Chinese
Patent Application No.201210364958.X, entitled "METHOD FOR IN SITU
CLEANING OF MOCVD REACTION CHAMBER", filed on Sep. 26, 2012 with
State Intellectual Property Office of PRC, which is incorporated
herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to semiconductor manufacture,
and in particular, to a method for in situ cleaning of a
Metal-Organic Chemical Vapor Deposition (MOCVD) reaction
chamber.
BACKGROUND OF THE INVENTION
[0003] At present, the MOCVD (Metal-Organic Chemical Vapor
Deposition) technology is widely used to prepare compounds of Group
III elements and Group V elements (such as GaN, InN, AN, InGaN,
AlGaN and GaP). In the state of the art, in an MOCVD reaction
chamber for the preparation of the compound of the Group III
element(s) and the Group V element(s), there is a main problem that
extra solid by-product deposits (such as carbonaceous organic
substances or metal and its compound(s)) may be generated in the
reaction chamber after each reaction step. These deposits are
deposited inside the reaction chamber (for example, at a shower
head, a susceptor and an inner wall), resulting in process drift
and degraded performance. Moreover, impurities such as particulates
are prone to be formed on a surface of a substrate during the
preparation of the compound of the Group III element(s) and the
Group V element(s), and these impurities may affect subsequent
processes. Therefore, the MOCVD reaction chamber needs to be
cleaned when being used, to remove the deposits inside the reaction
chamber and to improve the quality of the prepared compound of the
Group III element(s) and the Group V element(s).
[0004] In the prior art, the deposits inside the MOCVD reaction
chamber are generally removed manually. Specifically, the MOCVD
reaction chamber is opened, and then the deposits at the shower
head and so on are removed manually. However, for the manual
removal, the productivity is low, the repeatability is poor, and
the cleaning efficiency is not high. For this reason, some methods
for in situ removal of the deposits inside the MOCVD reaction
chamber are developed in the prior art. In these methods, the gas
containing halide(s) (such as Cl.sub.2, HCl and HBr) is introduced
into the MOCVD reaction chamber to remove the deposits in situ. For
this kind of cleaning method, the MOCVD reaction chamber does not
need to be opened, the repeatability is good, the cleaning
efficiency is high and the productivity is high.
[0005] However, on the surfaces with a relatively low temperature
(for example, the surface of the shower head undergone water
cooling, or the surface of the inner wall of the reaction chamber),
precursors of metal organic compound are decomposed incompletely
and form extra deposits. These extra deposits mainly contain
relatively stable organic ligands or related polymers and metal and
its compound(s). These relatively stable organic ligands or related
polymers are mainly highly concentrated carbonaceous organic
substances. In this case, this kind of in situ cleaning based on
the simple halide(s) (such as Cl.sub.2, HCl and HBr) has no effect
on the removal of the deposits on the surfaces with the relatively
low temperature.
SUMMARY OF THE INVENTION
[0006] For the capability of removing deposits on surfaces with a
relatively low temperature inside an MOCVD reaction chamber, the
embodiments of the present invention provide a method for in situ
cleaning of deposits inside the MOCVD reaction chamber. The method
includes:
[0007] performing Step a, including:
[0008] introducing a first cleaning gas into the reaction chamber,
and converting the first cleaning gas into a first plasma inside
the reaction chamber; and/or,
[0009] converting the first cleaning gas into the first plasma
outside the reaction chamber, and introducing the first plasma into
the reaction chamber; and/or,
[0010] introducing the first cleaning gas into the reaction
chamber, and maintaining a temperature inside the reaction chamber
in a range of 200.degree. C. to 500.degree. C.; and
[0011] maintaining a pressure inside the reaction chamber in a
first predetermined pressure range for a first time period to
completely remove a carbonaceous organic substance inside the
reaction chamber and convert a metal and its compound inside the
reaction chamber into a metallic oxide; wherein the first cleaning
gas includes a first oxygen-containing gas; and
[0012] performing Step b, including:
[0013] introducing a second cleaning gas into the reaction chamber,
and converting the second cleaning gas into a second plasma inside
the reaction chamber; and/or,
[0014] converting the second cleaning gas into the second plasma
outside the reaction chamber, and introducing the second plasma
into the reaction chamber; and/or,
[0015] introducing the second cleaning gas into the reaction
chamber, and maintaining the temperature inside the reaction
chamber in a range of 200.degree. C. to 500.degree. C.; and
[0016] maintaining the pressure inside the reaction chamber in a
second predetermined pressure range for a second time period to
completely remove the metallic oxide inside the reaction chamber;
wherein the second cleaning gas includes a first halogen-containing
gas.
[0017] preferably, the first cleaning gas further includes Ar;
and/or, the second cleaning gas further includes Ar.
[0018] Preferably, the first cleaning gas further includes a second
halogen-containing gas including one of HCl, BCl.sub.3, Cl.sub.2, a
gas mixture of H.sub.2/Cl.sub.2, HBr or any combination
thereof.
[0019] Preferably, in the first cleaning gas, the mole fraction of
the first oxygen-containing gas is larger than the mole fraction of
the second halogen-containing gas.
[0020] Preferably, the second cleaning gas further includes a
second oxygen-containing gas including one of O.sub.2, O.sub.3,
CO.sub.2, H.sub.2O.sub.2, N.sub.2O, CO or any combination
thereof
[0021] Preferably, in the second cleaning gas, the mole fraction of
the first halogen-containing gas is larger than the mole fraction
of the second oxygen-containing gas.
[0022] Preferably, the first oxygen-containing gas includes one of
O.sub.2, O.sub.3, CO.sub.2, H.sub.2O.sub.2, N.sub.2O or any
combination thereof.
[0023] Preferably, the first halogen-containing gas includes one of
HCl, BCl.sub.3, a gas mixture of BCl/O.sub.2, a gas mixture of
H.sub.2/Cl.sub.2, Cl.sub.2, HBr or any combination thereof
[0024] Preferably, the first time period is longer than 5 minutes
and the second time period is longer than 3 minutes.
[0025] In the embodiments of the present invention, the
carbonaceous organic substances inside the reaction chamber are
removed by using the first cleaning gas including a first
oxygen-containing gas and/or the plasma of the first cleaning gas,
and the metal(s) and its compound(s) inside the reaction chamber
are removed by using the second cleaning gas including the
halogen-containing gas and/or the plasma of the second cleaning
gas. The method for in situ cleaning of the MOCVD reaction chamber
according to the embodiments of the present invention is capable of
removing deposits containing relatively stable organic ligands or
related polymers and metal and its compound(s), and therefore has a
good cleaning effect for the deposits on the surfaces with a
relatively low temperature inside the reaction chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The drawings used in the description of the embodiments or
the prior art will be described briefly as follows, so that the
technical solutions according to the embodiments of the present
invention or according to the prior art will become clearer. Like
reference numerals refer to like components in the drawings. It is
obvious that the drawings in the following description are only
some embodiments of the present invention. For those skilled in the
art, other drawings may be obtained according to these drawings
without any creative work. In the drawings, the same reference
numerals indicate the same parts. The drawings may not be drawn to
scale, so as not to unnecessarily obscure the essential of the
present invention.
[0027] FIG. 1 is a flowchart of a method for in situ cleaning of an
MOCVD reaction chamber according to a first embodiment of the
invention;
[0028] FIG. 2 is a schematic structural diagram of the MOCVD
reaction chamber according to the embodiments of the invention;
[0029] FIG. 3 is a flowchart of a method for in situ cleaning of an
MOCVD reaction chamber according to a second embodiment of the
invention; and
[0030] FIG. 4 is a flowchart of a method for in situ cleaning of an
MOCVD reaction chamber according to a third embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0031] To make the object, technical solutions and advantages of
the invention clearer, in the following, the technical solutions in
embodiments of the present invention are described clearly and
completely in conjunction with the drawings. It is obvious that the
described embodiments are only some of the embodiments of the
present invention. Other embodiments obtained by those skilled in
the art on the basis of the embodiments of the present invention
without creative work fall into the scope of protection of the
present invention.
[0032] In order to solve the problem in the prior art that deposits
on surfaces with a relatively low temperature inside an MOCVD
reaction chamber can not be removed effectively, a method for in
situ cleaning of an MOCVD reaction chamber is proposed by the
inventors after research, which will be described in detail in the
following.
First Embodiment
[0033] FIG. 1 shows a flowchart of a method for in situ cleaning of
an MOCVD reaction chamber according to the first embodiment of the
invention. In the following, the method will be explained in detail
in conjunction with a schematic structural diagram (i.e., FIG. 2)
of the MOCVD reaction chamber.
[0034] Step S101: introducing a first cleaning gas into a reaction
chamber 10, and converting the first cleaning gas into first plasma
inside the reaction chamber 10, and maintaining the pressure inside
the reaction chamber 10 in a first predetermined pressure range for
a first time period, to remove carbonaceous organic substances
inside the reaction chamber 10 and to convert metal(s) inside the
reaction chamber 10 into metallic oxide(s).
[0035] Specifically, the first cleaning gas in the first embodiment
of the present invention may include a first oxygen-containing gas
which may be one of O.sub.2, O.sub.3, CO.sub.2, H.sub.2O.sub.2,
N.sub.2O or any combination thereof. Preferably, the first
oxygen-containing gas in the embodiment of the present invention
includes gas having strong oxidizability, such as O.sub.3 and
H.sub.2O.sub.2.
[0036] If the first cleaning gas only includes one type of gas, the
gas may be introduced into the reaction chamber 10 through one
intake duct (such as intake duct 41 or 42); and if the first
cleaning gas includes multiple types of gases, the multiple types
of gases may be introduced into the reaction chamber 10 through
multiple intake ducts, to ensure that these gases are introduced
into the reaction chamber 10 separately, that is, these gases are
not mixed until they enter into the reaction chamber 10. Moreover,
if the first cleaning gas includes multiple types of gases, these
gases may also be mixed before being introduced into the reaction
chamber 10, and then the mixed gas is introduced into the reaction
chamber 10 through the intake duct 41 or 42.
[0037] In Step S101, the first cleaning gas is converted into the
plasma after entering into the reaction chamber 10. Specifically,
an RF (radio frequency) voltage with a certain power may be applied
between a shower head 11 and a susceptor 13 inside the reaction
chamber 10, and the first cleaning gas is converted into the first
plasma by the RF voltage in a reaction region M inside the reaction
chamber 10 (for example, the reaction region may be a region
between the shower head 11 and the susceptor 13, where the
susceptor 13 is used to place substrates to be processed for
preparing a compound of Group III element(s) and Group V
element(s)). Moreover, the first cleaning gas may also be converted
into the first plasma in a region inside the reaction chamber 10
other than the reaction region M. Specifically, the RF voltage with
a certain power may be applied between an inner wall of the
reaction chamber 10 and the susceptor 13, or the RF voltage with a
certain power may be applied between the inner wall of the reaction
chamber 10 and the shower head 11. The first cleaning gas is
converted into the first plasma by the RF voltage in the region
other than the reaction region M (the region inside the reaction
chamber 10 other than the reaction region M in FIG. 2). Certainly,
in the first embodiment of the invention, the way to convert the
first cleaning gas into the plasma is not limited to such two ways,
and other common ways in the art may also be used, and it will not
be repeated herein.
[0038] After the first cleaning gas is converted into the first
plasma inside the reaction chamber 10, the pressure inside the
reaction chamber is maintained in a first predetermined pressure
range (for example, 0.1 Torr to 10 Torr) for a first time period
(for example, longer than 5 minutes), so that the first cleaning
step (i.e. the step of removing the carbonaceous organic substances
inside the reaction chamber) is carried out adequately. For
example, the pressure inside the reaction chamber may be maintained
in a range of 0.1 Torr to 10 Torr for 5 minutes to 30 minutes.
Those skilled in the art may properly select the pressure inside
the reaction chamber and the reaction time as required in the
practical cleaning, which would not be listed herein.
[0039] During the cleaning, the gas exhausting device 12 may be
kept in an open state, so that, in one aspect, the gaseous product
generated after the first plasma reacts with the deposits inside
the reaction chamber 10 may be discharged continuously from the
reaction chamber to speed up the course of cleaning and to improve
the cleaning effect, and in another aspect, the pressure inside the
reaction chamber 10 may also be maintained at a certain level to
meet the requirement during the cleaning That is, in the first
embodiment, the pressure inside the reaction chamber 10 may also be
controlled by controlling the degree of opening of the gas
exhausting device 12. That is to say, the pressure inside the
reaction chamber 10 may be controlled by controlling the gas
displacement of the gas exhausting device 12.
[0040] In this step, the first oxygen-containing gas (O.sub.2,
H.sub.2O.sub.2 or the like) is mainly utilized to convert the
carbonaceous organic substances in the deposits inside the reaction
chamber into gaseous carbon-oxygen compounds due to the
oxidizability of the first oxygen-containing gas, and the gaseous
carbon-oxygen compounds are discharged from the reaction chamber 10
through the gas exhausting device 12, so the organic substances
inside the reaction chamber 10 are removed. In addition, the
oxygen-containing gas may also oxidize some of the metals and their
compounds in the deposits inside the reaction chamber 10 into
metallic oxides which are easier to be removed in subsequent
steps.
[0041] In addition, the deposits inside the reaction chamber 10
generally are the mixture of the carbonaceous organic substances
and metal and its compound(s). In the case where the deposits are
thick, the carbonaceous organic substances at the bottom layer of
the deposits are covered by the metal and its compound(s) at the
upper layer of the deposits, and therefore it may be not possible
to completely convert the carbonaceous organic substances in the
deposits into the gaseous carbonaceous compounds by only using the
first cleaning gas with oxidizability. Therefore, for the purpose
that the carbonaceous organic substances in the deposits react
adequately, in this step, the first cleaning gas may further
include a certain amount of second halogen-containing gas. In this
case, the metal and its compound(s) above the carbonaceous organic
substances are prone to react with the second halogen-containing
gas to generate gaseous metal halide(s) which may be discharged
from the reaction chamber 10 by the gas exhausting device 12. For
example, the metal and its compound(s) such as GaN, InN or AlN
usually remain inside the MOCVD reaction chamber. The plasma of the
second halogen-containing gas (such as Cl.sub.2) inside the
reaction chamber 10 may react with the metal and its compound(s)
such as GaN, InN and AlN to generate gaseous GaCl.sub.3, InCl,
AlCl.sub.3 and so on.
[0042] The main object of Step S101 is to remove the carbonaceous
organic substances inside the reaction chamber. Therefore, in this
step, in the first cleaning gas, the mole fraction of the
oxygen-containing gas may be larger than the mole fraction of the
second halogen-containing gas, and the second halogen-containing
gas may include one of HCl, BCl.sub.3, Cl.sub.2, a gas mixture of
H.sub.2/Cl.sub.2 (in this application, the term "gas mixture of
H.sub.2/Cl.sub.2" represents "the gas mixture of H.sub.2 and
Cl.sub.2", and other similar terms represent similar meaning), HBr
or any combination thereof. Of course, this is only one preferable
embodiment, and in practice, in the first cleaning gas, the
proportion between the mole fraction of the oxygen-containing gas
and the mole fraction of the second halogen-containing gas may not
be limited thereto.
[0043] Moreover, in order to improve the cleaning effect and the
speed of cleaning, in this step, the first cleaning gas may further
include a certain amount of Ar. Ar may be converted into the plasma
of Ar inside the reaction chamber 10. The plasma of Ar is capable
of speeding up the cleaning reaction (including the reaction of the
reducing gas with the carbonaceous organic substances and/or the
reaction of the halogen-containing gas with the metal and its
compound(s)).
[0044] Under the condition of appropriate temperature, appropriate
pressure and the like, the plasma converted from the first cleaning
gas may break the carbon bond of the carbonaceous organic
substances or carbonaceous polymers and react with the carbonaceous
organic substances or carbonaceous polymers to generate the gaseous
carbonaceous compounds. Thus, the relatively stable organic ligands
and polymers inside the reaction chamber are converted into highly
active substances which may be easily removed. The thus obtained
substances may be drawn away from the reaction chamber along with a
gas flow by a pump under the particular condition of gas flow,
pressure, temperature and so on, thereby achieving the purpose of
cleaning.
[0045] It should be noted that, in the first embodiment of the
present invention, any one or both of the following Steps S101-A1
and S101-A2 may be performed in place of Step S101.
[0046] Step S101-A1: converting the first cleaning gas into the
first plasma outside the reaction chamber 10, and introducing the
first plasma into the reaction chamber 10;
[0047] Step S101-A2: introducing the first cleaning gas into the
reaction chamber 10, and maintaining the temperature inside the
reaction chamber 10 in a range of 200.degree. C. to 500.degree.
C.
[0048] The first cleaning gas in Step S101-A1 and Step S101-A2 may
have the same meaning as the first cleaning gas in Step S101. Here
the expressing of "have the same meaning" means that the first
cleaning gas herein has a same range as the first cleaning gas in
Step S101 (for example, both include the first oxygen-containing
gas). However, any different kind of gas in this range may be
selected. The expressing of "have the same meaning" in the
following is in the same case.
[0049] Moreover, Step S101-A1 and Step S101-A2 may be carried out
while Step S101 is being carried out, to further speed up the
cleaning reaction.
[0050] Step S102: introducing a second cleaning gas into the
reaction chamber 10, and converting the second cleaning gas into
second plasma inside the reaction chamber 10, and maintaining the
pressure inside the reaction chamber 10 in a second predetermined
pressure range for a second time period, to remove the metal and
its compound(s) inside the reaction chamber 10.
[0051] In the first embodiment of the invention, the second
cleaning gas may include a first halogen-containing gas which may
be one of HCl, BCl.sub.3, Cl.sub.2, a mixture of H.sub.2/Cl.sub.2
gas, HBr or any combination thereof.
[0052] Specifically, the second cleaning gas may be introduced into
the reaction chamber 10 through the intake duct 41 or 42. After
Step S101, the carbonaceous organic substances inside the reaction
chamber 10 are substantially removed, and the remainder is mainly
metal (such as Ga, Al and In) and its compound(s). Therefore, in
this step, the second cleaning gas including the halogen-containing
gas is introduced into the reaction chamber 10. The second cleaning
gas may be converted into the plasma in the reaction region M or
the region inside the reaction chamber 10 other than the reaction
region M under the action of the RF voltage (referring to the
description in Step S101). The plasma is capable of adequately
reacting with the metal and its compound(s) remained in the
deposits to generate the gaseous metal halide, and then the gaseous
metal halide is discharged from the reaction chamber 10 by the gas
exhausting device 12.
[0053] After the second cleaning gas is converted into the plasma
inside the reaction chamber 10, the pressure inside the reaction
chamber is maintained in a second predetermined pressure range (for
example, 0.1 Torr to 10 Torr) for a second time period (for
example, longer than 3 minutes), so that the second cleaning step
(i.e. the step of removing the metal and its compound(s)) is
adequately carried out to completely remove the metal and its
compound(s) remained inside the reaction chamber. For example, the
pressure inside the reaction chamber may be maintained in a range
of 0.1 Torr to 10 Torr for 5 minutes to 30 minutes. Those skilled
in the art may properly select the pressure inside the reaction
chamber and the reaction time as required in the practical
cleaning, which would not be listed herein. Furthermore, a few of
metallic oxides generated in Step S101 also may be removed in this
step.
[0054] Specifically, the pressure inside the reaction chamber 10
may be controlled by controlling the flow rate of the second
cleaning gas introduced into the reaction chamber 10.
Alternatively, the pressure inside the reaction chamber 10 may be
controlled by controlling the degree of opening of the gas
exhausting device 12.
[0055] In this step, the halogen which is converted into the plasma
reacts with the metal and its compound(s) remained inside the
reaction chamber and the metallic oxide(s) generated in step S101,
to convert the remained metal and its compound(s) and the metallic
oxide(s) into the gaseous metal halide(s) and discharge the gaseous
metal halide(s) from the reaction chamber 10. For example, the
metal and its compound(s) such as Ga, In, Al, GaN, InN and AlN are
usually prone to remain inside the MOCVD reaction chamber. The
plasma of the second halogen-containing gas (such as Cl.sub.2)
inside the reaction chamber 10 may react with the metal and its
compound(s) such as Ga, In, Al, GaN, InN and AlN to generate
gaseous GaCl.sub.3, InCl, AlCl.sub.3 and so on.
[0056] Moreover, in Step S102, the second cleaning gas may also
include a certain amount of oxygen-containing gas (such as
O.sub.2). The oxygen-containing gas may be converted into plasma
inside the reaction chamber 10, and then react with the
carbonaceous organic substances which may be remained inside the
reaction chamber 10, to completely remove the carbonaceous organic
substances in the deposits, and to further improve the cleaning
effect.
[0057] The main object of Step S102 is to remove the metal and its
compound(s) and a few of metallic oxides inside the reaction
chamber. Therefore, in this step, in the second cleaning gas, the
mole fraction of the first halogen-containing gas may be larger
than the mole fraction of the second oxygen-containing gas. Of
course, this is only a preferable embodiment, and in practice, in
the second cleaning gas, the proportion between the mole fraction
of the first halogen-containing gas and the mole fraction of the
second oxygen-containing gas may not be limited thereto.
[0058] Furthermore, in order to further improve the cleaning effect
and the speed of cleaning, in this step, the second cleaning gas
may further include a proper amount of Ar. Ar may be converted into
the plasma of Ar inside the reaction chamber 10. The plasma of Ar
is capable of speeding up the cleaning reaction.
[0059] It should be noted that, in the first embodiment of the
invention, any one or both of the following Step S102-B1 and Step
S102-B2 may be carried out in place of Step S102.
[0060] Step S102-B1: converting the second cleaning gas into the
second plasma outside the reaction chamber 10, and introducing the
second plasma into the reaction chamber 10;
[0061] Step S102-B2: introducing the second cleaning gas into the
reaction chamber 10, and maintaining the temperature inside the
reaction chamber 10 in a range of 200.degree. C. to 500.degree.
C.
[0062] The second cleaning gas in Step S102-B1 and Step S102-B2 may
have the same meaning as the second cleaning gas in Step S102.
[0063] Moreover, Step S102-B1 and Step S102-B2 may be carried out
while Step S102 is being carried out, to further speed up the
cleaning reaction.
[0064] In the method for in situ cleaning of the MOCVD reaction
chamber provided in the first embodiment of the present invention,
firstly, the first cleaning gas including the first
oxygen-containing gas is introduced into the reaction chamber and
converted into the plasma inside the reaction chamber, and the
carbonaceous organic substances inside the reaction chamber are
removed by utilizing the oxidizability of the first cleaning gas;
then the second cleaning gas including the first halogen-containing
gas is introduced into the reaction chamber and converted into the
plasma inside the reaction chamber to remove the metal and its
compound(s) and a few metallic oxides remained inside the reaction
chamber, thereby the deposits inside the MOCVD reaction chamber are
removed completely.
[0065] It should be noted that, in the first embodiment of the
invention, Step S101 and Step S102 may be carried out in
succession, that is, Step S102 is carried out immediately after
Step S101 is completed. Alternatively, Step S101 and Step S102 may
also be carried out intermittently, that is, Step S102 is carried
out after a period of time since Step S101 is completed. Of course,
during the period of time, the gas exhausting device 12 may always
be kept in an exhausting state, so the gaseous product generated in
Step S101 is completely discharged from the reaction chamber and
the cleaning efficiency of Step S102 may further be improved.
[0066] It should be noted that, in the first embodiment of the
invention, the duration for carrying out Step S101 and/or Step S102
may be properly extended, to completely remove the carbonaceous
organic substances inside the reaction chamber by Step S101 and
completely remove the metal and its compound(s) inside the reaction
chamber by Step S102. Technician may monitor whether the
carbonaceous organic substances and/or the metal and its
compound(s) inside the reaction chamber are removed completely by
using an assistant detection device. Since it is not the focus of
this application, it will not be described in detail herein.
[0067] Moreover, in the embodiment of the invention, Step S101 and
Step S102 may also be carried out repeatedly, to further improve
the cleaning effect.
[0068] In the following, the technical solutions according to the
first embodiment of the present invention are described in detail
with two specific examples.
FIRST EXAMPLE
[0069] A: O.sub.2, Cl.sub.2 and Ar are introduced into the reaction
chamber 10 simultaneously, for example, through the intake ducts
shown in FIG. 2 at the flow rate of 250 sccm, 250 sccm and 500
sccm, respectively. A RF voltage is applied between the shower head
11 and the inner wall of the reaction chamber 10 with a power
maintained at 2000 W and an RF frequency of 13.56 MHz. The internal
pressure of the reaction chamber 10 is kept to be 0.72 Torr, and
the reaction time period of the plasma is 10 minutes (i.e., the
predetermined time period is 10 minutes). After this step, most of
the deposits inside the reaction chamber 10 are removed.
[0070] B: HCl and Ar are introduced into the reaction chamber 10
simultaneously at the flow rate of 500 sccm for each of HCl and Ar.
An RF voltage is applied between the inner wall of the reaction
chamber 10 and the shower head 11 with the RF power maintained to
be 2000 W and the RF frequency of 13.56 MHz, the pressure inside
the reaction chamber is maintained to be 0.68 Torr and the reaction
time of the plasma lasts for 5 minutes (i.e. the second time period
is 5 minutes). After this step, all of the deposits inside the
reaction chamber may be removed.
SECOND EXAMPLE
[0071] A: O.sub.2, Cl.sub.2 and Ar are introduced into the reaction
chamber 10 simultaneously, for example, through the intake ducts
shown in FIG. 2 at the flow rate of 250 sccm, 250 sccm and 500
sccm, respectively. An RF voltage is applied between the inner wall
of the reaction chamber 10 and the shower head 11 with the RF power
maintained to be 2000 W and the RF frequency maintained to be 13.56
MHz, the pressure inside the reaction chamber is maintained to be
0.72 Torr and the reaction time of the plasma lasts for 10 minutes.
After this step, most of the carbonaceous organic substances in the
deposits inside the reaction chamber are removed. In addition, in
this step, the oxygen-containing gas may also react with some of
metals and their compounds to generate metallic oxides.
[0072] B: H.sub.2, Cl.sub.2 and Ar are introduced into the reaction
chamber 10 simultaneously at the flow rate of 250 sccm, 250 sccm
and 500 sccm, respectively. An RF voltage is applied between the
inner wall of the reaction chamber 10 and the shower head 11 with
the RF power maintained to be 2000 W and the RF frequency
maintained to be 13.56 MHz, and the pressure inside the reaction
chamber is maintained to be 0.68 Torr and the reaction time of the
plasma lasts for 5 minutes. After this step, most of the
carbonaceous organic substances, the metals and their compounds and
the metallic oxides in the deposits inside the reaction chamber 10
may be removed;
[0073] Since H.sub.2 and Cl.sub.2 are usually introduced into the
MOCVD reaction chamber during the preparation of the compound of
Group III element(s) and Group V element(s) in the MOCVD, in this
step, a gas mixture of H.sub.2 and Cl.sub.2 is employed to remove
the metal and its compound in the deposits, thus there is no need
to add an extra gas into the reaction chamber 10. Therefore, not
only the cleaning process but also the cleaning apparatus for the
MOCVD reaction chamber may be simplified (i.e. no excessive intake
duct needs to be added).
[0074] It should be noted that, in the embodiment of the invention,
in the course of the in situ cleaning of the MOCVD reaction chamber
(such as Step S101, Step S101-A1, Step S102 and Step S102-B1), the
reaction chamber 10 may be heated to maintain the temperature
inside the reaction chamber 10 at a certain level. In this way, not
only the speed of in situ cleaning can be improved, but also it can
be ensured that the by-product generated after the reaction of the
plasma with the deposits is gaseous. Therefore, it is avoided that
the by-product remains inside the reaction chamber when it meets
the surfaces with a relatively low temperature and becomes liquid
or solid. For example, the temperature inside the reaction chamber
10 may be maintained in a range of 70.degree. C. to 100.degree. C.
(such as 70.degree. C., 80.degree. C. or 100.degree. C.).
Specifically, the temperature inside the reaction chamber may be
maintained by heating the outer wall or the inner wall of the
reaction chamber.
[0075] In the method for cleaning the MOCVD reaction chamber in the
embodiment of the invention, the reducing plasma is used to react
with the deposits to convert the deposits into the gaseous
products, which are discharged from the reaction chamber by the gas
exhausting device. In the case where the deposits inside the MOCVD
reaction chamber (particularly the deposits on the surfaces with a
relatively low temperature) are removed by using the in situ
cleaning method according to the first embodiment of the present
invention, the process may be stable, the performance may be
improved and the whole MOCVD process may be performed
automatically.
[0076] It should be noted that the method for in situ cleaning of
the MOCVD reaction chamber according to the embodiments of the
invention may also be implemented in other ways. For example, the
plasma may be generated inside the reaction chamber. Alternatively,
the plasma may be generated outside the reaction chamber and then
be introduced into the reaction chamber.
Second Embodiment
[0077] A method for in situ cleaning of an MOCVD reaction chamber
according to the second embodiment of the invention is similar to
the method according to the first embodiment of the invention. The
difference lies in that, in the second embodiment of the invention,
plasma may be generated outside the reaction chamber 10, and then
the plasma may be introduced into the reaction chamber via an
intake duct. For simplicity, only the difference of the second
embodiment from the first embodiment of the invention is described
here. For those skilled in the art, it is easy to obtain other
contents about the second embodiment of the invention from the
related description in the first embodiment of the invention, and
it will not be repeated herein.
[0078] Step S301: converting a first cleaning gas into first plasma
outside a reaction chamber 10, introducing the first plasma into
the reaction chamber 10, and maintaining the pressure inside the
reaction chamber 10 in a first predetermined pressure range for a
first time period, to remove carbonaceous organic substances inside
the reaction chamber 10 and to convert some of the metals and their
compounds into metallic oxides.
[0079] The first cleaning gas in the second embodiment of the
present invention may include a first oxygen-containing gas which
may be one of O.sub.2, O.sub.3, CO.sub.2, H.sub.2O.sub.2, N.sub.2O
or any combination thereof. Preferably, in the embodiments of the
present invention, a gas having strong oxidizability, such as
O.sub.3 or H.sub.2O.sub.2, is selected as the first
oxygen-containing gas.
[0080] Specifically, the first plasma may be generated by employing
a plasma converting device. For example, the first
oxygen-containing gas may be introduced into the plasma converting
device firstly, and then the first oxygen-containing gas may be
converted into the first plasma inside the plasma converting
device. The first plasma may be introduced into the reaction
chamber through a gas intake device connected to the reaction
chamber.
[0081] After the first plasma is introduced into the reaction
chamber, the pressure inside the reaction chamber is maintained in
a first predetermined pressure range for a first time period. For
example, the pressure inside the reaction chamber may be maintained
in a range of 0.1 Torr to 10 Torr (as an example of the first
predetermined pressure range) for more than 5 minutes (for example,
5 minutes to 30 minutes), so that the first plasma reacts with the
carbonaceous organic substances in the deposits.
[0082] It should be noted that, in the second embodiment of the
invention, any one or both of the following Step S301-A1 and Step
S301-A2 may be carried out in place of Step S301.
[0083] Step S301-A1: introducing the first cleaning gas into the
reaction chamber 10, and converting the first cleaning gas into the
first plasma inside the reaction chamber 10;
[0084] Step S301-A2: introducing the first cleaning gas into the
reaction chamber 10, and maintaining the temperature inside the
reaction chamber 10 in a range of 200.degree. C. to 500.degree.
C.
[0085] The first cleaning gas in Step S301-A1 and Step S301-A2 may
have the same meaning as the first cleaning gas in Step S301.
[0086] Moreover, Step S301-A1 and Step S301-A2 may be carried out
while Step S301 is being carried out, to further speed up the
cleaning reaction.
[0087] Step S302: converting a second cleaning gas into second
plasma outside the reaction chamber 10, and introducing the second
plasma into the reaction chamber 10, and maintaining the pressure
inside the reaction chamber 10 in a second predetermined pressure
range for a second time period, to remove metal and its compound(s)
inside the reaction chamber 10.
[0088] Specifically, the second plasma may be generated by using a
plasma converting device. For example, the second cleaning gas may
firstly be introduced into the plasma converting device and then
may be converted into the second plasma inside the plasma
converting device.
[0089] After the second plasma is introduced into the reaction
chamber 10, the pressure inside the reaction chamber 10 may be
maintained in a range of 0.1 Torr to 10 Torr (as an example of the
second predetermined pressure range) for more than 3 minutes (for
example, 5 minutes to 30 minutes), so that the second plasma
adequately reacts with the metal and its compound(s) remained in
the deposits to generate a gaseous metal halide and the gaseous
metal halide is discharged from the reaction chamber by a gas
exhausting device.
[0090] The first cleaning gas in the second embodiment of the
invention has the same meaning as that in the first embodiment of
the invention, and the second cleaning gas in the second embodiment
of the invention has the same meaning as that in the first
embodiment of the invention.
[0091] It should be noted that, the description of parameters (such
as the pressure, the time and the temperature), composition and
content of the gas and so on in the first embodiment of the
invention is also applicable to the solution in the second
embodiment of the invention, which will not be repeated herein for
succinctness. However, for those skilled in the art, a specific
implementation may be obtained by combining the solution in the
second embodiment of the invention with the corresponding content
in the first embodiment of the invention, which falls into the
scope of protection of the invention.
[0092] In the second embodiment of the invention, the first
cleaning gas is converted into the first plasma and the second
cleaning gas is converted into the second plasma outside the
reaction chamber 10. The first plasma is introduced into the
reaction chamber 10 to completely remove the carbonaceous organic
substances inside the reaction chamber 10 and the second plasma is
introduced into the reaction chamber 10 to completely remove the
metal and its compound(s) inside the reaction chamber.
[0093] It should be noted that, in the second embodiment of the
invention, Step S301 and Step S302 may be carried out in
succession, that is, Step S302 is carried out immediately after
Step S301 is completed. Alternatively, Step S301 and Step S302 may
be carried out intermittently, that is, Step S302 is carried out
after a period of time since Step S301 is completed. Certainly,
during the period of time, the gas exhausting device 12 may always
be kept in an exhausting state, so the gaseous product generated in
Step S301 is completely discharged from the reaction chamber and
the cleaning efficiency of Step S302 may further be improved.
[0094] In the above-mentioned first and second embodiments, it is
mainly described in detail that the plasma (the first and/or second
plasma) is used to remove the deposits (the carbonaceous organic
substances and/or the metal and its compound(s)) inside the
reaction chamber. However, in practice, the deposits inside the
reaction chamber may also be removed by the thermal reaction of the
cleaning gas with the deposits, according to additional embodiments
of the invention.
Third Embodiment
[0095] The third embodiment of the invention provides a method for
in situ cleaning of an MOCVD reaction chamber, which is similar to
the method in the first embodiment of the invention. The difference
lies in that, in the third embodiment of the invention, the
deposits inside the reaction chamber is removed by the thermal
reaction of the cleaning gas with the deposits. For simplicity,
only the difference of the third embodiment from the first
embodiment of the invention is described in the third embodiment of
the invention. For those skilled in the art, it is easy to obtain
other contents about the third embodiment of the invention from the
related description in the first embodiment of the invention, which
will not be repeated herein.
[0096] Step S401: introducing a first cleaning gas into a reaction
chamber 10, and maintaining the temperature inside the reaction
chamber 10 in a range of 200.degree. C. to 500.degree. C., and
maintaining the pressure inside the reaction chamber 10 in a first
predetermined pressure range for a first time period, to remove a
carbonaceous organic substances inside the reaction chamber 10 and
to convert some of metals and their compounds into metallic
oxides.
[0097] In the third embodiment of the present invention, the first
cleaning gas may include a first oxygen-containing gas which may be
one of O.sub.2, O.sub.3, CO.sub.2, H.sub.2O.sub.2, N.sub.2O or any
combination thereof. Preferably, in the embodiments of the present
invention, a gas having strong oxidizability, such as O.sub.3 or
H.sub.2O.sub.2, is selected as the first oxygen-containing gas.
[0098] Specifically, the pressure inside the reaction chamber 10
may be maintained in a first predetermined pressure range (for
example, 0.1 Torr to 10 Torr) by heating an inner wall and/or a
susceptor 13 and/or a shower head 11 of the reaction chamber 10,
and the temperature inside the reaction chamber 10 may be
maintained in a range of 200.degree. C. to 500.degree. C. (such as
200.degree. C., 300.degree. C. or 500.degree. C.), so the first
plasma reacts with the carbonaceous organic substances in the
deposits. By using the method, the carbonaceous organic substances
in the deposits inside the reaction chamber 10 may be removed
completely in only one step.
[0099] It should be noted that, in the third embodiment of the
invention, any one or both of the following Step S401-A1 and Step
S401-A2 may be carried out in place of Step S401.
[0100] Step S401-A1: introducing the first cleaning gas into the
reaction chamber 10, and converting the first cleaning gas into
first plasma inside the reaction chamber 10;
[0101] Step S401-A2: converting the first cleaning gas into the
first plasma outside the reaction chamber 10, and introducing the
first plasma into the reaction chamber 10.
[0102] The first cleaning gas in Step S401-A1 and Step S401-A2 may
have the same meaning as the first cleaning gas in Step S401.
[0103] Moreover, Step S401-A1 and Step S401-A2 may be carried out
while Step S401 is being carried out, to further speed up the
cleaning reaction.
[0104] Step S402: introducing a second cleaning gas into the
reaction chamber 10, maintaining the temperature inside the
reaction chamber 10 in a range of 200.degree. C. to 500.degree. C.,
and maintaining the pressure inside the reaction chamber 10 in a
second predetermined pressure range for a second time period, to
remove the metallic oxides inside the reaction chamber 10.
[0105] After the second cleaning gas is introduced into the
reaction chamber 10, the pressure inside the reaction chamber 10
may be maintained in a range of 0.1 Torr to 10 Torr (as an example
of the second predetermined pressure range) for more than 3 minutes
(for example, 5 minutes to 30 minutes), so that the second cleaning
gas has a complete thermal reaction with the metal and its
compound(s) remained in the deposits to generate a gaseous metal
halide which is discharged from the reaction chamber by a gas
exhausting device.
[0106] The first cleaning gas in the third embodiment of the
invention has the same meaning as that in the first embodiment of
the invention, and the second cleaning gas in the third embodiment
of the invention has the same meaning as that in the first
embodiment of the invention.
[0107] It should be noted that, in the third embodiment of the
invention, Step S401 and Step S402 may be carried out in
succession, that is, Step S402 is carried out immediately after
Step S401 is completed. Alternatively, Step S401 and Step S402 may
be carried out intermittently, that is, Step S402 is carried out
after a period of time since Step S401 is completed. Certainly,
during the period of time, the gas exhausting device 12 may always
be kept in an exhausting state, so the gaseous product generated in
Step S401 is completely discharged from the reaction chamber and
the cleaning efficiency of Step S402 may further be improved.
[0108] It should be noted that, the description of parameters (such
as the pressure, the time and the temperature), the composition and
content of the gas and so on in the first embodiment and/or the
second embodiment of the invention is also applicable to the
solution in the third embodiment of the invention, which will not
be repeated herein for succinctness. However, for those skilled in
the art, a specific implementation may be obtained by combining the
solution in the third embodiment of the invention with the
corresponding content in the first embodiment and/or the second
embodiment of the invention, which falls into the scope of
protection of the invention.
[0109] Thus, in the embodiments of the invention, the deposits
inside the reaction chamber may be removed by the thermal reaction
of the cleaning gas with the deposits. Moreover, the deposits
inside the reaction chamber may also be removed by firstly
converting the cleaning gas into the plasma and then making the
plasma react with the deposits. The plasma may be generated outside
the reaction chamber, or may be generated inside the reaction
chamber (may be generated in the reaction region inside the
reaction chamber, or may be generated in the region inside the
reaction chamber other than the reaction region). Furthermore, by
using the solution in the above-mentioned embodiments of the
invention, the carbonaceous organic substances and the metal and
its compound(s) in the deposits inside the reaction chamber may be
removed completely by only one step.
[0110] The forgoing descriptions are only the preferred embodiments
of the present invention, and it should be noted that numerous
improvements and modifications made to the present invention can be
made by those skilled in the art without departing from the
principle of the present invention, and those improvements and
modifications shall fall into the scope of protection of the
invention.
* * * * *